ID 1434 -
Kwas liponowy
PL: Kwas liponowy
EN: Alpha Lipoic acid (ALA)
Pdf: alpha-lipoic acid
Oświadczenie (2)
- metabolizm tłuszczu
- właściwości antyoksydacyjne
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claims is alpha-lipoic acid.
Alpha-lipoic acid, also known as thioctic acid, is a non-essential sulphur-containing food constituent structurally well-defined and present in foods generally bound to protein (lipoyllysine) at very low concentrations (around 0.3 mg/100 g for the richest natural sources, i.e., spinach for vegetables and kidney for meat). The natural compound is the R enantiomer, while in food supplements generally the racemic form (R/S) is used. It exists in redox forms, the oxidised form with a closed cycle containing a disulfide bond or a reduced form, with an open ring containing two thiol groups (dihydrolipoic acid). Alpha-lipoic acid is measurable in foods by established methods.
The Panel considers that the food constituent, alpha-lipoic acid, which is the subject of the health claims is sufficiently characterised.
2.1. Ochrona lipidów we krwi przed uszkodzeniem oksydacyjnym (ID 1434, 3134)
The claimed effects are “antioxidant properties” and “fat metabolism”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects relate to the protection of body lipids from oxidative damage caused by free radicals.
Reactive oxygen species (ROS) including several kinds of radicals are generated in biochemical processes (e.g., respiratory chain) and as a consequence of exposure to exogenous factors (e.g. radiation, pollutants). These reactive intermediates damage biologically relevant molecules such as DNA, proteins and lipids if they are not intercepted by the antioxidant network which includes free radical scavengers like antioxidant nutrients.
The Panel considers that protection of body lipids from oxidative damage may be a beneficial physiological effect.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka
The major metabolic role of alpha-lipoic acid is to act as a coenzyme in important metabolic pathways, especially decarboxylation of α-ketoacids, in which it functions in association with thiamine and nicotinamide containing enzymes.
Thirty seven references have been provided to support the claimed effects, consisting of 14 narrative reviews, 5 human studies, 11 animal studies in rat or mouse models of diabetes and two in vitro studies. References unrelated to the food constituent, to the claimed effects, or using parenteral routes of administration of the food constituent or performed in patients not representative of the target population (e.g., diabetic patients with poor glycaemic control and albuminuria) were not considered pertinent for the substantiation of the claimed effects.
3.1. Ochrona lipidów we krwi przed uszkodzeniem oksydacyjnym (ID 1434, 3134)
One randomised controlled trial in humans, which was provided in the consolidated list, was considered pertinent for the substantiation of the claimed effect.
In the study by Marangon et al. (1999) a total of 31 healthy adults were supplemented for two months either with alpha-lipoic acid alone (600 mg/d, n =16), with alpha-tocopherol alone (400 IU/d, n=15), and then with the combination of both for two additional months. At baseline, and after two and four months of supplementation, urine F2-isoprostanes, low-density lipoprotein (LDL) susceptibility to oxidation and plasma protein carbonyls was assessed. The Panel notes the absence of an appropriate control group and the lack of a direct statistical comparison between the alpha-lipoic acid and the alpha-tocopherol interventions, which greatly limit the conclusions that can be drawn from this study for the substantiation of the claimed effect.
From the narrative reviews provided with the consolidated list, alpha-lipoic acid is a well recognised antioxidant due to its low redox potential: it scavenges hydroxyl radicals, hypochlorous acid, and singlet oxygen. It does not scavenge hydrogen peroxide or superoxide radical and probably does not scavenge peroxyl radicals; it may chelate transition metals involved in oxidation reactions; it also appears to increase intracellular glutathione. In addition, dihydrolipoic acid, readily formed in the body from alpha-lipoic acid, appears to be able to regenerate other antioxidants, such as ascorbate and (indirectly) vitamin E, from their radical forms. However, most of the data comes from in vitro studies and animal models of diabetes, which do not predict the occurrence of an effect by the consumption of alpha-lipoic acid on the protection of body lipids from oxidative damage in humans.
The Panel concludes that a cause and effect relationship has not been established between the consumption of alpha-lipoic acid and the protection of body lipids from oxidative damage.
Warunki i możliwe ograniczenia stosowania oświadczenia
200-600 mg per day